textproduct: Albany

WHAT HAS CHANGED

Low probabilities still exist for hazardous impacts resulting from the scattered to numerous snow showers that will occur across the region this morning through this afternoon. However, some of the latest guidance has shown increasing trends for isolated to scattered, moderate to heavy snow showers across portions of the Southern Adirondacks, western Mohawk Valley, Eastern Catskills, Capital Region, Taconics, Berkshires, and Southern Greens. Probabilities for brief, 1" per hour snowfall rates in these areas are maximized at 10-30%, making it a very low threat. That said, should localized, heavier snow showers occur, heavier rates combined with gusty winds could briefly pose significant reductions to visibility from mid to late morning into early this afternoon. This threat will impact the morning commute and potentially the afternoon commute.

Otherwise, no changes were made that would alter the integrity of the previous forecast.

KEY MESSAGES

1) Scattered to numerous snow showers will pose a 10-30% chance of 1" per hour snowfall rates across higher elevations and the Capital Region from this morning into this afternoon, potentially resulting in brief reductions to visibility for the morning and afternoon commutes today.

2) No hazardous weather conditions are anticipated from Wednesday through early next week.

DISCUSSION

KEY MESSAGE 1...

Our CWA is currently surrounded almost on all sides with surface lows and waves beneath broad troughing aloft and an embedded, positively-tilted shortwave whose axis currently extends south and west through the eastern Great Lakes and into the Ohio Valley. A stationary boundary to our north near the International Border strings together a surface cyclone over western New York and one well to our northeast while a surface trough extends into the Mid-Atlantic near/along a cool frontal boundary trailing behind the western New York low. Throughout the morning, as the upper-level shortwave digs south and east further into New York State and the western Ohio Valley/eastern Mid-Atlantic, the surface trough to our south will surge northeastward, deepen slightly and ultimately merge with the primary western New York low that will track eastward and slightly weaken. An occluded boundary will form between the two low centers, enhancing surface forcing for ascent as the upper shortwave encroaches further to provide the upper-level component of lift.

Ongoing snow showers will increase in coverage and actually begin to reach the ground (latest obs indicate latest reflectivity scans are mere virga) by daybreak as forcing is enhanced by the approach of the front, the passage of the primary surface low, and the passage of a narrow band of FGEN at 850 hPa. Latest forecast soundings indicate that initial low- level dry air should be easily overcome by the increased vertical motion and subsequent moistening of the column. That said, HiRes guidance has also begun to indicate that there could also be some embedded heavier snow showers across portions of the region. Strong UVVs intersecting a moist or moistening DGZ across portions of the Southern Adirondacks, western Mohawk Valley, Eastern Catskills, Capital Region, Taconics, Berkshires, and Southern Greens suggest snowfall rates could be come briefly moderate to locally heavy (0.5-1" per hour) by mid to late morning into this afternoon. Steep lapse rates and weak, though present, surface instability support the thought that an isolated to scattered number of these could closely resemble, though not quite meet criteria of, snow squalls. Now, that said, latest HREF and NBM probabilities for 1" per hour snowfall rates and visibilities under 0.5 statute miles only range from about 10-30% with the greatest of these across the highest elevations of the aforementioned locations where orographic enhancement of snowfall is likely the driving factor. But, as ground temperatures have been rather mild, driving the expectation that widespread accumulations will not result on road surfaces, and gusty winds are already expected as a result of this system, we felt it pertinent to mention this as brief, potentially significant, reductions to visibility will likely be the primary impact from these snow showers. This is especially true as gusty winds could pose at least some reduction to visibility outside of the aforementioned heavier snow showers even if roadways are nothing but wet. That said, with low dew points and already cooler than normal temperatures in a cold- advecting environment, there is certainly potential for isolated to scattered patches of slick road conditions so it is still important for motorists to be cautious. These conditions could pose some inconvenience to the morning and afternoon commutes today.

The greatest accumulations are anticipated across the higher elevations of the Southern Adirondacks, western Mohawk Valley, Eastern Catskills, Taconics, Berkshires, and Southern Greens where anywhere from 1-2" is possible. Locally higher amounts of 3-4" are possible in the highest elevations of the Southern Greens, but these were not widespread enough to warrant a Winter Weather Advisory. Across the Capital Region where there is potential for some of those heavier showers, a quick 0.5-1.5" is possible, but most accumulations will only be seen on grassy surfaces. Elsewhere, only a dusting to a couple tenths is expected. Additionally, portions of the immediate Capital District and lower Mid-Hudson Valley, thermal profiles become a bit marginal this afternoon, alluding to the fact that some rain could be mixed in with snow. So we maintained a mention of a light mix and even some plain rain in these areas this afternoon. Freezing rain, however, is not anticipated as a lack of a sufficient warm nose will mitigate melting and wetbulb effects will likely maintain a mostly snow precipitation type.

KEY MESSAGE 2...

High pressure swiftly builds in across the region at the surface tonight in the wake of the departing system. Following closely behind is build of an upper-level ridge aloft which, in tandem with the surface high, will remain in place through at least Thursday. Fair weather conditions and moderating temperatures can be expected throughout this time as a result. The only factor that will challenge the steady state of these conditions will be a passing upper-level low to our north and the passage of its trailing cold front Friday into Saturday. This could result in some rain showers across the region, but confidence is low in this element of the forecast at this time as the best forcing will be well to our north and there may be a fair amount of dry air to overcome to actually see precipitation reach the surface. Regardless, high pressure is progged to build in quickly behind this front as well with a stronger upper-level cyclone over the Southeast forcing a stronger ridge over our region Sunday into early next week. This will ultimately reinforce pleasant weather across eastern New York and western New England with well above- normal temperatures that will certainly be perfect for outdoor activities.

AVIATION /09Z TUESDAY THROUGH SATURDAY/

Through 06z/Wed...Clipper system remains on track to cross the region overnight through Tuesday. Scattered snow showers are expected to pass near or over KALB/KPSF/KGFL between 08-13z/Tue where some brief IFR/MVFR cigs/vsbys are expected. Due to the scattered nature, have maintained a PROB30 at these sites. Most of the activity looks to pass to the north and west of KPOU so have trended this site dry through 12z/Tue. An additional band of mixed rain/snow showers will cross mainly KALB/KGFL/KPSF between 13-17z/Tue where another brief period of IFR conditions are possible. A second PROB30 was used for this period. Lighter and more isolated showers are likely at KPOU so included just a VCSH due to uncertainty in reductions of cigs or vsbys. Behind this line of showers, drier weather returns with cigs returning to VFR. Another isolated snow shower could pass near KPSF but due to low confidence have left it out of the TAF at this time. Clearing occurs this evening as high pressure builds in from the west.

Light to calm winds tonight will become variable at less than 10 kt after 12z/Tue. Winds abruptly shift to the west to northwest behind the secondary line of showers and increase to around 15 kt with gusts 25 to 30 kt. Wind begins to diminish after 00z/Wed.

Outlook...

Wednesday Night: No Operational Impact. NO SIG WX. Thursday: Low Operational Impact. Breezy. NO SIG WX. Thursday Night: No Operational Impact. NO SIG WX. Friday: Low Operational Impact. Slight Chance of SHRA. Friday Night: Moderate Operational Impact. Chance of SHRA. Saturday: No Operational Impact. NO SIG WX. Saturday Night: No Operational Impact. NO SIG WX. Sunday: No Operational Impact. NO SIG WX.

ALY WATCHES/WARNINGS/ADVISORIES

CT...None. NY...None. MA...None. VT...None.